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| 晚新生代以来青藏高原东缘的剥蚀过程:来自裂变径迹的证据 |
| 张毅,李勇,周荣军,A.L.Densmore,N.J.Richardson |
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(1. 成都理工大学 油气藏及开发工程国家重点实验室, 四川 成都 610059;
2. 四川省地震局 工程地震研究所, 四川 成都 610041;
3. Institute of Geology, Department of Earth Sciences, ETH Zentrum, CH-8092 Zǜrich Sw itzerland) |
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| 摘要: |
| 本文以青藏高原东缘的三级地貌(川西高原、龙门山和四川盆地)单元为基础,利用裂变径迹定年数据分区块研究了该地区的晚新生代以来的剥蚀速率。研究结果表明,晚白垩世以来青藏高原东缘经历了一个由平缓到突然加速的剥蚀过程,其转折点为中新世。在整个时间段内的平均剥蚀速率,川西高原为0.26mm/yr,龙门山为0.72mm/yr,四川盆地为0.20mm/yr。龙门山的剥蚀速率大约是川西高原的2.8倍,间接反映边缘山脉的隆升并不等同于高原内部的隆升,边缘山脉的隆升可能是构造隆升和剥蚀隆升相叠加的结果。 |
| 关键词: 青藏高原东缘 晚新生代 裂变径迹 剥蚀速率 隆升 |
| DOI： |
| 附件 |
| 投稿时间：2005-08-02修订日期：2006-01-23 |
| 基金项目:国家自然科学基金项目(40372084)和四川省重点学科建设项目(SZD0408)。 |
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| The denudation of the eastern margin of the Qinghai-Xizang Plateau since the Late Cenozoic: Evidence from the fission-track ages |
| ZHANG Yi, LI Yong, ZHOU Rong-jun, A. L. Densmore, N. J. Richardson |
(1. Chengdu University of Technology, Chengdu 610059, Sichuan, China;
2. Sichuan Seismological Bureau, Chengdu 610041, Sichuan, China;
3. Institute of Geology, Department of Earth Sciences, ETH Zentrum, CH-8092 Zurich Switzerland) |
| Abstract: |
| The denudation rates of the eastern margin of the Qinghai-Xizang Plateau since the Late Cenozoic are examined for the third-order geomorphological units western Sichuan plateau,Longmen Mountains and Sichuan Basin on the basis of the fission-track ages for the samples from different blocks in the study area.The findings show that there are gradations of denudation from slow processes before the Miocene to rapid ones after the Miocene.The mean denudation rate is 0.26 mm/yr for the western Sichuan plateau, 0.72 mm/yr for the Longmen Mountains,and 0.20 mm/yr for the Sichuan Basin.It can be seen that the mean denudation rate for the Longmen Mountains is about 2.8 times than that for the western Sichuan plateau,implying that the uplift of the marginal mountain ranges does not means that of the Plateau;the former may be combination of tectonic uplift and denudational uplift. |
| Key words: eastern margin of the Qinghai-Xizang Plateau Late Cenozoic fission-track age denudation rate uplift |